react-native-scan-code-cn/index.js at master · AXGithub/react-native-scan-code-cn · GitHub

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import React from 'react'
import {
    View,
    requireNativeComponent,
    NativeModules,
    Platform,
    Dimensions,
    StatusBar,
    findNodeHandle
} from 'react-native'

type
EventCallbackArgumentsType = {
    nativeEvent: Object,
};

const NativeBarCode = requireNativeComponent('RNScanCode', RNScanCode)

export const ScanCodeModule = NativeModules.ScanCodeModule || NativeModules.RNScanCodeManager

const EventThrottleMs = 500;

let _this = null

export class RNScanCode extends React.Component {
    constructor(props) {
        super(props)
        this._lastEvents = {};
        this._lastEventsTimes = {};
        _this = this
        const {width, height} = Dimensions.get('window')
        let _height = height + (Platform.OS === 'ios' ? 0 : StatusBar.currentHeight)
        this.state = {
            surfaceWidth: width,
            surfaceHeight: _height
        };
    }

    static Constants = {
        CodeType: ScanCodeModule.CodeType
    };

    _lastEvents: { [string]: string };
    _lastEventsTimes: { [string]: Date };
    // 存储组件实例的tag值
    _scancodeHandle: ?number = 0;

    _onObjectDetected = (callback: ?Function) => ({nativeEvent}: EventCallbackArgumentsType) => {
        const {type} = nativeEvent;
        if (
            this._lastEvents[type] &&
            this._lastEventsTimes[type] &&
            JSON.stringify(nativeEvent) === this._lastEvents[type] &&
            new Date() - this._lastEventsTimes[type] < EventThrottleMs
        ) {
            return;
        }
        if (callback) {
            callback(nativeEvent);
            this._lastEventsTimes[type] = new Date();
            this._lastEvents[type] = JSON.stringify(nativeEvent);
        }
    };

    /** 查找对应组件实例的tag值 */
    _setReference = (ref: ?Object) => {
        if (ref) {
            this._scancodeHandle = findNodeHandle(ref);
        } else {
            this._scancodeHandle = null;
        }
    }

    /** 设置手电筒 */
    static setFlashlight(flash) {
        if (Platform.OS === 'ios') {
            ScanCodeModule.setFlashlight(_this._scancodeHandle, flash)
        } else {
            ScanCodeModule.setFlashlight(flash)
        }
    }

    render() {
        const {
            children,
            style,
            onLightBright,
            onBarCodeRead,
            codeTypes = Object.values(ScanCodeModule.CodeType),
            ...otherProps
        } = this.props
        const {surfaceWidth, surfaceHeight} = this.state
        return (
            <View style={{flex: 1, backgroundColor: 'green'}} onLayout={event => {
                this.setState({surfaceHeight: event.nativeEvent.layout.height})
            }}>
                <NativeBarCode
                    style={{width: surfaceWidth, height: surfaceHeight}}
                    {...otherProps}
                    codeTypes={codeTypes}
                    onBarCodeRead={this._onObjectDetected(onBarCodeRead)}
                    onLightBright={this._onObjectDetected(onLightBright)}
                    ref={this._setReference}
                />
                <View style={[{position: 'absolute', top: 0, left: 0}, style]} pointerEvents="box-none">
                    {children}
                </View>
            </View>
        )
    }
}